The Guardian’s Paul Lewis and Rob Evans on investigating one of England’s most covert police units and learning that they were using the identities of dead children. Frank Bennett reflects on the impact of discovering that a police spy had stolen his dead brother’s identity to infiltrate two leftwing organisations, and to deceive a woman into a sexual relationship The Undercover Police Scandal: Love and Lies Exposed is available now on ITVX. Help support our independent journalism at theguardian.com/infocus